The sum of the interior angles of a convex polygon is $900^\circ$. How many sides does the polygon have?
Answer: For a convex polygon with $n$ sides, the sum of its interior angles will be $(n-2)180^\circ$. Thus, if $(n-2)180^\circ=900^\circ$, then we must have $n-2=5$, so $n=\boxed{7}$ sides.